SOLDER JOINT STRUCTURE, POWER MODULE, HEAT-SINK-ATTACHED SUBSTRATE FOR POWER MODULE, METHOD FOR PRODUCING SAID SUBSTRATE, AND PASTE FOR FORMING SOLDER UNDERLAYER

摘要

A solder joint structure, a power module utilizing the joint structure, a heat-sink-attached substrate for a power module, a method for producing the substrate, and a paste for forming a solder underlayer. The paste is arranged on a metallic member and then fired, thereby reacting with an oxide coating film generated on the surface of the metallic member to form a solder underlayer on the metallic member. In this manner, it becomes possible to prevent the formation of swells or wrinkles on the surface of an aluminum member and it also becomes possible to improve the reliability of the joint between the aluminum member and a member to be joined to the aluminum member even under applying a power cycle or a heat cycle.